According to statistics issued by a Cisco visual network index (VNI), more than 90% of internet traffic in 2011 is file sharing, videos and web pages. According to its forecast, this proportion will continue to increase, and it is estimated that only video traffic will occupy 54% of entire internet traffic by 2016.
When acquiring such contents as files, videos, web pages and the like, different users usually request for a same content repeatedly. An existing IP network is host-centric, and if a transmission of a content is to be performed, an end-to-end connection needs to be established, namely: each user is required to establish a connection with an original content provider respectively, and then the original content provider sends a content requested by the user wholly to the user. In this approach, on one hand, the original content provider needs to handle with a large number of user requests, easily causing slow response or even denial of service; on the other hand, links in the network need to transmit a same content many times, causing waste of network resources. Therefore, how to effectively submit a content is a difficult problem of the current internet.
In recent years, the academia has started to research on how to transform the traditional host-centric IP network into a content-centric IP network. What is more representative is an NDN (Named Data Networking) project and the like supported by Future Internet Architecture (FIA) of U.S. National Science Foundation (NSF), as well as a PSIRP (Publish-Subscribe Internet Routing Paradigm) project and the like supported by European Seventh Framework Program (Framework Program 7, FP7). Most of these projects propose to cache a content and respond to a content request by means of a cache of a network device (e.g., a router), namely: the network device may determine to cache the content or not when submitting the content, and when forwarding the content request, return a result immediately if hitting the local cache.
At present, most of solutions are as follows: each network device on a path from the user to the original content provider determine to return the content to the user or forward the request according to whether the local cache hits the content or not. However, since the cache of the network device is limited, not all contents may be cached, meanwhile, a study shows that the content request has a regional characteristic (i.e., users with close geographical locations may request similar contents), hit rates of a same content in different caches are different (that is, different contents may be cached in different network devices), therefore, the cache in the network could not be effectively utilized by performing routing in the existing path calculating manner.